New Delhi: While majority of the country is dealing with diseases of Dengue and Chikungunya, it is reported 33 patients in the capital have tested positive for bacteria borne disease “Scrub Typhus”. The disease is commonest occurring rickettsial infection in India, in which a patient experiences similar symptoms of that of Chikungunya, but unlike chikungunya where treatment includes no antibiotics, this can be treated using antibiotics to kill bacteria.

According to a report by HT, 150 patients tested by All India Institute of Medical Sciences (AIIMS) for the disease, 33 have tested positive. Here are some important points that practitioners need to know about the disease.

Scrub typhus is an infection, which is transmitted through the larval mites or “chiggers” belonging to the family Trombiculidae. Only the larval stages take blood meal. A number of small rodents particularly wild rats of subgenus 12 Rattus are natural hosts for scrub typhus. The field rodent and vector mites act as reservoir and between the two the infection perpetuates in nature.

The symptoms of the disease include rashes, high fever and other symptoms similar to that of chikungunya. However, complications start occurring if untreated after first week of illness that include Jaundice, renal failure, pneumonitis, acute respiratory distress syndrome (ARDS), septic shock, myocarditis and meningoencephalitis are various complications known with this disease.

Scrub typhus can occur in areas where scrub vegetation- consisting of low lying trees and bushes is encountered, and also in habitats as diverse as banks of rivers, rice fields, poorly maintained kitchen gardens 8, grassy lawns which can all be inhabited by chiggers. The chiggers, too small to be seen by the naked eye, feed usually on rodents and accidentally on humans, and transmit the infection during the prolonged feeding which can last 1-3 days.

The complications of scrub typhus usually develop after the first week of illness. Jaundice, renal failure, pneumonitis, acute respiratory distress syndrome (ARDS), septic shock, myocarditis and meningoencephalitis are various complications known with this disease 24. Pneumonia is one of the most frequent complications of scrub typhus which manifests as a non-productive cough and breathlessness and leads to ARDS which could be life-threatening. Severe complications besides acute respiratory distress syndrome (ARDS) include hepatitis, renal failure, meningo-encephalitis and myocarditits with shock may occur in varying proportions of patients

Prompt antibiotic therapy, even based on suspicion, shortens the course of the disease lowers the risk of complications and in turn reduces morbidity and mortality due to rickettsial diseases. Currently, doxycycline is regarded as the drug of choice.

In 2015, DHR-ICMR came out with guidelines FOR DIAGNOSIS AND MANAGEMENT OF RICKETTSIAL DISEASES IN INDIA. Following are its major recommendations for the treatment of scrub typhus.

Treatment

There is paucity of evidence based on randomized controlled trials for the management of rickettsial diseases including scrub typhus.

These guidelines for treatment cover the most common infection, the scrub typhus, murine typhus and Indian Tick typhus and do not cover acute Q fever though treatment of Q fever is on similar lines.

Without waiting for laboratory confirmation of the Rickettsial infection, antibiotic therapy should be instituted when rickettsial disease is suspected.

At Primary level: The Health Care provider needs to do the following:

a) Recognition of disease severity. If the patients come with complications to primary health facility and treating physician considers it as rickettsial infection, treatment with doxycycline should be initiated before referring the patient.

b) Referral to secondary or tertiary centre in case of complications like ARDS, acute renal failure, meningo-encephalitis, multi-organ dysfunction. In addition to recommended management of community acquired pneumonia, doxycycline is to be initiated when scrub typhus is considered likely.

c) In fever cases of duration of 5 days or more where malaria, dengue and typhoid have been ruled out; following drugs should be administered when scrub typhus is considered likely –

Adults

a) Doxycycline 200 mg/day in two divided doses for individuals above 45 kg for duration of 7 days. Patients should be advised to swallow capsules with plenty of fluid during meals while sitting or standing

Or

b) Azithromycin 500 mg in a single oral dose for 5 days.

Children

a) Doxycycline in the dose of 4.5 mg/kg body weight/day in two divided doses for children below 45 kg

Or

b) Azithromycin in the single dose of 10mg/kg body weight for 5 days.

Pregnant women

a) Azithromycin 500 mg in a single dose for 5 days.

b) Azithromycin is the drug of choice in pregnant women, as doxycycline is contraindicated

At secondary and tertiary care:

a) The treatment as specified above in uncomplicated cases.

b) In complicated cases the following treatment is to be initiated –

i) Intravenous doxycycline (wherever available) 100mg twice daily in 100 ml normal saline to be administered as infusion over half an hour initially followed by oral therapy to complete 7-15 days of therapy.

Or

ii) Intravenous Azithromycin in the dose of 500mg IV in 250 ml normal saline over 1 hour once daily for 1-2 days followed by oral therapy to complete 5 days of therapy.

Or

iii) Intravenous chloramphenicol 50-100 mg/kg/d 6 hourly doses to be administered as infusion over 1 hour initially followed by oral therapy to complete 7-15 days of therapy.

iv) Management of the individual complications should be done as per the existing practices. Doxycycline and/or Chloramphenicol resistant strains have been seen in South-East Asia. These strains are sensitive to Azithromycin.

Meghna A Singhania is the founder and Editor-in-Chief at Medical Dialogues. An Economics graduate from Delhi University and a post graduate from London School of Economics and Political Science, her key research interest lies in health economics, and policy making in health and medical sector in the country.
She can be contacted at meghna@medicaldialogues.in.
Contact no. 011-43720751

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